Comment by keb_
Yeah, as others already mentioned, I think they sat on their laurels for a bit too long and let VSCode overtake it.
For what it's worth, I went from ST3 -> VSCode -> ST4, and have been happy since. I've found that I prefer my text editor with minimal extensions, and with Sublime Text's LSP Plugin, I'm pretty content. The performance and customizable UI make it more worth it to me than VSCode.
It's the LSP plugin that finally drove me to leave ST4 for Zed. Language integration is table stakes for an editor now. The fact that ST support is behind a volunteer plugin instead of integrated directly in the editor just means it's never going to be as good as a editor that does have first class support. The ST devs need to actually improve the editor, but I haven't seen any material updates in years.